Rotary filling machine

ABSTRACT

A ROTARY FILLING MACHINE HAVING SPACED CAM-CONTROLLED FILLER HEADS OR UNITS WITH DEPENDING FILLING STEMS WHICH ARE AUTOMATICALLY LOWERED AND RAISED FOR ACCURATE MATERIAL, FILLING OF CONTAINERS OR BOTTLES OF ANY SUITABLE MATERIAL, EACH FILLER HEAD WHEN LOWERED ENTERS ITS FILLING STEM IN THE OPENING OR NECK OR A CONTAINER, SEALING AND AIR SENSING ITS CONTAINER BEFORE FILLING, AND REJOICING A DEFECTIVE CONTAINER WHEREBY ONLY THOSE CONTAINERS WHICH ARE LEAKPROOF UNDER AIR PRESSURE ARE FILLED WITH THE DESIRED VOLUME OF THE LIQUID PRODUCE. THE FILLING HEAD OR UNIT INCLUDES A FLEXIBLE SENSING DIAPHRAGM AND A PORTED PLUNGER PROVIDING AN AIR VALVE, AND A FLEXIBLE DIAPHRAGM AND PLUNGER HAVING A VALVE CONTROLLING PRODUCT FLOW, EACH OPERATED BY AN AIR FLOW SYSTEM, AND VACUUM SIGNALS DETERMINING WHEN TO COMMENCE FILLING AND WHEN TO STOP.

P 20, 1971 J. A. RISSER ROTARY FILLING MACHINE 6 Sheets-Sheet 1 Filed Aug. 4. 1969 T-d i I U h l llll llllllllkllllllllllllllllHlllHHl Sept. 20, 1971 J. A. RISSER ROTARY FILLING MACHINE Filed Aug. 4, 1969 6 Sheets-Sheet 2 80 o I 66 j 6 XX Z3 15 ]E\ II I! 1 4 Met-21511 games Q.E' am J5; Lbljolnfl- Q i.

J." A. RISSER 3,605,827

ROTARY FILLING MACHINE Sept. 20, 1971 6 Sheets-Sheet 5 Filed Aug. 4. 1969 p 19171 J. A. RISSER 3,605,827

ROTARY FILLING MACHINE Filed. Aug. 4. 1969 6 Sheets-Sheet 4 QWW U Sept. 20, 1971 J. A. RISSER ROTARY FILLING MACHINE 6 Sheets-Sheet 5 Filed Aug. 4, 1969 United States Patent 3,605,827 ROTARY FILLING MACHINE James A. Risser, Northbrook, Ill., assignor to US. Bottlers Machinery Company, Chicago, Ill. Filed Aug. 4, 1969, Ser. No. 847,182 Int. Cl. B65b 3/26 US. Cl. 141-39 9 Claims ABSTRACT OF THE DISCLOSURE A rotary filling machine having spaced cam-controlled filler heads or units with depending filling stems which are automatically lowered and raised for accurate level filling of containers or bottles of any suitable material, each filler head when lowered enters its filling stern in the opening or neck of a container, sealing and air sensing its container before filling, and rejecting a defective container whereby only those containers which are leakproof under air pressure are filled with the desired volume of the liquid product. The filling head or unit includes a flexible sensing diaphragm and a ported plunger providing an air valve, and a flexible diaphragm and plunger having a valve controlling product flow, each operated by an air flow system, and vacuum signals determining when to commence filling and when to stop.

Among the objects of the present invention is the provision in a filling machine of a novel filler unit having means for sensing defective containers incapable of holding fluid pressure such as those with a hole or chipped neck and the rejection of such an imperfect container before initiating the filling operation.

The novel air sensing unit triggers the filler mechanism and includes an air sensing diaphragm, diaphragm-actuating piston rod and cam for actuating the piston rod effecting mechanical triggering of a product valve and start the flow of the product into a leak-proof container.

The filler head comprehends the provision of two synthetic diaphragms and two plunger mechanisms operated by air flow systems generating pressure, and vacuum signals to determine when filling commences and when filling stops. One of the diaphragms with its plunger etfects sensing of the container and the other diaphragm and its plunger controls product flow.

In the sensing operation air at low pressure is blown into the container through a small vent in the filling stem after the neck of the container is sealed and thus determines whether the container is sound or leaks. Unless an internal pressure greater than atmospheric can be developed within the container the product diaphragm and product diaphragm valve will not be actuated to permit product to flow into a container which leaks and this container is subsequently discarded.

In the present invention the liquid product for filling the containers is delivered by pressure so that filling speed is dependent upon the size of the orifice, the product and the pressure delivered to the one-piece filler tube unit consisting of telescoping tubes open at their lower end, the inner or central one being a vent tube and the outer a concentric filling tube.

Another important object of the present invention is the complete elimination of an overflow system and the elimination of air ejection into the product that may occur by means of air blowing as a means of sensing.

The present invention comprises a no-drip filling system for handling a wide range of product viscosity by em bodying a positive shut-off valve in the head assembly. Due to the reduced velocity of the product entering the container at the end of the filling cycle, and the slower height changes in the containers being filled, results in optimum accuracy in filling.

Patented Sept. 20, 1971 "ice Another advantage of the present fill system is the ability to change the fill height by adjusting the position of the sensing vent tube by raising the circular ring cam actuating the plural tube heads. Also there is an absence of a vacuum acting on the product which may tend to vaporize or cause flashing of certain products and which may cause the product to become more foamy and diflicult to handle.

The present invention further comprehends a filling systern so constructed and arranged as to be self-sealing and in which product flow is shut off in the event of any air or mechanical failure, the construction being such that all product entering the unit is blown out, resulting in a. clean system after each cycle and avoiding any product entering from solidifying or hardening in the air passageways. Thus the entire filling system is easily and readily maintained clean with a minimum of product residue at the end of all runs.

Further objects are to provide a construction of maximum simplicity, efficiency, economy and ease of assembly and operation, and such further objects, advantages and capabilities as will later more fully appear and are inherently possessed thereby.

In the drawings:

FIG. 1 is a view in side elevation of the novel filling machine.

FIG. 2 is a view in side elevation of a sensing diaphragm assembly in the upper housing of the filler head, including a sensing diaphragm, reciprocable piston rod and means for controlling the air pressure and vacuum to the filling tube assembly.

FIG. 3 is a view in front elevation of the filler head and tube assembly with the filler tube lowered into the container or bottle and the latter sealed.

FIG. 4 is a View, part in vertical cross section and part in side elevation, of the filler head and tube assembly of FIG. 3 with the bottle sealed, the sensing piston rod and its sensing diaphragm being in neutral position and the product diaphragm and valve for dispensing the liquid in closed position.

:FIG. 5 is an enlarged view in horizontal cross section taken on the line 4-4 of FIG. 3.

FIG. 6 is a view, part in horizontal cross section and part in top plan of the sensing housing and assembly of FIG. 5 and showing the path of air flow.

FIG. 7 is another vertical cross sectional view through the sensing diaphragm assembly in the upper section of the filler head and the base showing the flow path of the air therethrough.

FIG. 8 is a view similar to FIG. 4 but showing the sensing diaphragm and its piston rod actuated to the position in which the product diaphragm and the product valve are lifted for dispensing the product in a sound bottle or container.

FIG. 9 is a cross sectional view similar to FIG. 5 through the upper housing of the filling tube assembly with the sensing diaphragm and its piston rod in the position of FIG. 8.

FIG. 10 is a cross sectional view through the sensing piston rod and product diaphragm assembly of FIGS. 8 and 9 and showing the path of the air flow in the filling operation.

FIG. 11 is a view similar to FIGS. 4 and 8 but showing the position of the sensing and product diaphragms with the bottle filled and the filling tube elevated, at which time the sensing diaphragm and its piston rod are moved rearwardly and the dispensed liquid product reaches the lower open end of the elevated vent tube when a vacuum is established in the vent system due to the liquid momentarily blocking the vent tube and shutting off the high pressure air line which is holding the product diaphragm and product valve open but now moved to closed position.

FIG. 12 is a view similar to FIGS. and 9 but with the sensing diaphragm and piston rod moved to the position in FIG. 11.

FIG. 13 is a vertical cross sectional view through the air/vacuum rotary distributing valve, the product inlet and the product distributing valve supplying the product to the successive filling tubes.

FIG. 14 is a plan view of the upper plate of the air/ vacuum distributing valve.

Referring to the disclosure in the drawings and to the novel illustrative embodiment shown, each of the plural filling tube assemblies 10 for a rotary filling machine shown in FIG. 1, comprise a filler head 11 having a depending filling stem 12 including a product tube 13 dispensing the liquid product and encompassing a centrally arranged inner vent tube 14 providing a unit assembly with both tubes being open at their lower end at 15.

Each filler head 11 is adapted to be lowered with the filler stem 12 into the neck or opening of any suitable container or bottle 16 by means of a ring cam 17 as hereinafter pointed out for filling the same, and as each container is being filled, its filler head with its filler stern and its concentric tubes is elevated by the ring cam 17 and withdrawn when its container is filled.

Containers or bottles 16 of any suitable material including plastic, glass or metal are fed to and enter the rotary filling machine by means of a conventional feed worm and star assembly as disclosed in Risser Pat. No. 3,150,697, of Sept. 29, 1964. Each head 11 with its filling stem 12 is lowered and raised to and from sensing and filling position by a ring cam 17. At an angular position on the filling machine and but slightly before the sealing rubber 18 on the filler stem is lowered into contact with the top or neck of the container 16, an air/vacuum rotary distributing valve 19 is indexed so that a low air pressure (approximately 2 to 4 p.s.i.g.) is initially delivered to the head 11 to clear the vents. This air pressure varies in accordance with the viscosity of the product being filled, the sealer rubber 18 making contact with the neck of the container 16 as shown in FIGS. 3 and 4.

Each filler stem 12 is attached by a threaded coupling 21 and sealing means to the base 22 of its filler head 11, and spaced below the coupling 21 and mounted on the stem is another coupling or mounting 23 carrying the sealer rubber 18 for contacting and sealing the neck of the container 16 when the filler head and its stem are lowered. This sealing contact is effected prior to filling when air under relatively low pressure is discharged into the container for sensing and determining whether the container is free of any defect making it unsuitable for use.

To supply air under relatively low pressure to the associated head, vent tube and container each depending filler stem is lowered under control of the cam 17 into an aligned container carried beneath a filler head and filling stem. In the sensing cycle, air under relatively low pressure (2 to 4 p.s.i.g.) from the inlet tube 24 enters the upper sensing unit 25 of the head in which is located a sensing diaphragm 26 carried adjacent one end of a piston rod or plunger 27 actuated by an actuating cam 28 and rod linkage 29 (see FIG. 2).

Positioning the sealing rubber 18 on the top of its container or bottle 16 aligns the actuating cam 28 with the rod linkage 29 that moves the piston rod 27 to the neutral position shown in FIGS. 3 to 7, inclusive. When in this neutral position (see FIG. 7) the piston rod initially open an air passageway 30 in the sensing unit 25 from the low pressure source, behind the sensing diaphragm 26, through an opening 39 in the piston rod 27 and down and out the connecting passageways 31 and 32 to the air vent 14 (see arrows). This efiects a vent blowing or clean-out cycle.

If no container or bottle 16 is disposed in alignment 4 below the lowered filler head and filler stem, the head assembly drops lower than when a container is present and engaged by the sealer rubber 18, whereby the actuating cam 28 misses the rod linkage 29 which actuates the sensing diaphragm piston rod 27 and the vent tube 14 is not blown clean onto the table top of the filling machine.

Each filler unit or assembly 10 comprises a filler head 11 including a sensing unit 25 with an upper housing 33 having a bore to receive the reciprocating piston rod 27 horizontally movable in the bore, one end of the piston rod projecting through a bearing 34 in one end of the housing and the other end of the piston rod projecting through an end housing section 35 at the other end of the housing and an intermediate wall 36. Mounted between the adjoining end of the housing 33 and the wall 36 is the flexible air sensing diaphragm 26 with the housing 33 provided with a recess 37 at the rear of the diaphragm open to air pressure or vacuum provided by the air passages 24 and 38 in the filler operation as hereinafter described.

The reciprocating piston rod 27 is of rectangular cross section and ported to function as an air valve, being provided with transverse openings 39, 41 and 42 and other openings or slots 43, 44 in its periphery to be aligned with the air passageways communicating with the air passages 24 and 38. Air under initially relatively low air sensing pressure (approximately 2 to 4 p.s.i.g.) enters the passage 24 through the hose conection 45 from the air/ vacuum rotary distributing valve 19.

At the exterior of the end housing 35 is a part 46 having laterally opening bores 47 and 48 each receiving a stainless steel ball 49 spring-biased inwardly by a coil spring 51 forcing the balls against the circumference of a rod extension 52 coupled to an end of the piston rod 27. When the piston rod is in neutral position, the balls engage the periphery of an annular enlargement 53 on the extension adjacent the groove or detent 54 as shown in FIG. 4. When the piston rod 27 is in the extended position of FIGS. 8 and 9, the balls 49 drop into the groove 54, and when the piston rod is in the retracted position of FIGS. 11 and 12, the balls drop onto the reduced diameter at 55 of the rod extension 52.

Below the housing 33 of the filler assembly is affixed the depending housing or base 22 carrying at its lower end the filling stem 12, this housing 22 comprising an upper section 56 attached by bolts 57 to the housing 33, an intermediate abutting section 58, and a lower section 59, the housing 33 and the upper section mounting therebetween a product diaphragm 61 afiixed to and carried by the upper end of a vertically reciprocal piston rod or plunger 62 carrying a product valve 63 at its lower end. This piston rod 62 is reciprocable in a bore in the intermediate member 56 with an expansion spring 64 hearing against a washer at the center of the diaphragm 61. This diaphragm is operable in a recess or chamber 66 in the adjacent faces of the housing 33 and the upper section 56.

The product valve 63 comprises an annular tapered sealing face and O-ring 68 mounted on the depending end of the piston rod 62 in a recess or chamber 69 in the intermediate section 58 and having sealing engagement with a tapered seat 71 for controlling flow of the product entering through the inlet 72 and chamber 69 and discharging through the outer concentric product filling tube 13 encompassing the vent tube 14.

In the positions shown in FIGS. 4 to 12, inclusive, the ported piston rod 27 functions as an air valve. In the position of FIGS. 4, 5, 6 and 7, which is the neutral position, air under relatively low pressure (approximately 2 to 4 p.s.i.g.) enters the passage 24 from an air/vacuum rotary valve 19. This valve has indexed itself so that the relatively low air pressure is delivered to the filler head 11, and with the air sensing piston rod 27 in the position shown, the air passage is blocked when the filler tube is being lowered into the container 16. When the sealer rubber 18 engages and seals the neck of the bottle and the air sensing piston rod 27 and its diaphragm 26 are in neutral position, air under relatively low pressure (approximately 2 to 4 p.s.i.g) blows through the inlet tube 24, passageway 30, through the transverse port 39 in the piston rod 27, and through the passageways 31 and 32 into the recess or chamber 74 and into and through the vent tube 14 into the container 16. The air under relatively low pressure clears out the vent tube. As shown in FIG. 7, the recess 74 is also open through the passage 73 to the rear of the diaphragm 26.

With the sealing rubber 18 in this sealing position, the low air pressure is next utilized to sense leakproof container through the inlet tube 24. With a sound sealed container or bottle 16, the air under the sensing pressure builds up in the container and through the passage 73 to the rear of the air sensing diaphragm 26, thereby actuating the air sensing piston rod 27 to the position shown in FIGS. 8, 9 and 10. If the container has a hole or defect allowing for the escape of the air pressure, the sensing piston rod 27 is not actuated and all component parts remain in the position shown in the neutral position of FIGS. 4 to 7, inclusive.

If no container is present below a filler head assembly, the latter drops slightly lower than if a container were present, in which lowered position the actuating cam 28 misses the rod linkage 29 which actuates the sensing diaphragm piston rod 27 and the vent tube 14 would not be blown clear and onto the table top of the filler mechanism. If the liquid product is rather light or highly fluid such as water, a slightly higher air pressure can be used but, if relatively heavy, an extremely low air pressure is all that is required to clear the vent 14.

Pushing the diaphragm outwardly as in FIGS. 8, 9 and 10, shifts the sensing piston rod 27 which is ported to function as a valve to the position shown in FIG. 9, keeping the air sensing track open from the valve 19 through the passageway 30, opening 41 in the piston rod 27, and passageway 31 down to the air vent tube 14 and around up to the chamber 37.

With the outward movement of the piston rod 27 and its air sensing diaphragm 26, a second air line fed from a flexible hose 75 delivers air under pressure ,of approximately to p.s.i.g. from a second air source to the passageway 38. This air under higher pressure passes through the air valve in wide open position (FIG. 10), through the air passage 76 and transverse port 42 of the piston rod 27, down an air passage 78 and under the product diaphragm 61. This air pressure acting on the product diaphragm 61 overcomes the pressure of the product diaphragm spring 64 and lifts the product valve 63 carried by the lower end of the product piston rod 62.

Upon completion of the forward motion of the sensing diaphragm piston rod 27, the stainless steel balls 49 drop into the annular groove or detent 54 adjacent the end of this piston rod, providing a braking or clutching means for retention of this piston rod 27 in this adjusted position.

With the product valve 63 opened by the higher air pressure disposed beneath the product diaphragm 61, the product commences to flow slowly while the container is yet sealed. However, when the sensing diaphragm piston rod 27 is fully extended with the balls 49 of the brake system dropped in the annular groove 54 adjacent the end of the rod 27, the tube assembly and its sealer rubber 18 are raised to unseal the bottle or container 16. This is effected by a slight inclination of the ring cam 17.

As soon as the bottle is open to the atmosphere, the flow of the product is increased and the low air pressure (approximately 2 to 4 p.s.i.g) in the passage 30 is now changed to a vacuum sensing shut-off pressure resulting from the air-vacuum distributing valve reaching an angular position which shifts from the air sensing pressure to a vacuum sensing shut-01f pressure, as will be later pointed out in connection with the structure and operation of this valve 19.

The product then flows at a high fill rate until approximately 75 to of the predetermined volume has been reached. By means of a shut-ofi shoe 79 in a product distributing valve 81, the opening for the product supply is reduced or choked thereby reducing the rate of flow. This variation in filling speed during the filling cycle permits the product to be brought quickly to a high level flow in the bottle or container, and then more slowly deliver the remaining required product volume, thus resulting in an accurate and positive fill level of the liquid or product being dispensed.

When the filling level reaches the open end 15 of the product vent of the filling tube 13, a vacuum is registered in the system due to the momentary clogging of the air vent tube 14. This vacuum is registered on the back of the sensing diaphragm 26 with this sensing diaphragm and its piston rod 27 shifting to the right as seen in FIG. 11, with the opening 43 being moved to shut off communication between the high pressure air supply in passage 76 and passage 78 leading to the product diaphragm 61. Also, the opening 41 is moved to shut 01f the vacuum to the chamber 37, but the initial vacuum, aided by additional vacuum force when the opening 39 is aligned with the passageways 30 and 3.1, is sufficient to shift the piston rod 27 to the position of FIGS. 11 and 12 where the balls 49, 49 of the clutch and ball arrangement are directed into the reduced diameter 55 of the rod extension 52.

In the position of FIGS. 11 and 12, the air/vacuum passageway is closed as both the openings 39 and 41 are out of alignment with the passageways 30 and 31, and the opening 42 is out of alignment with the passages 76 and 78 to positively shut off the high pressure air supply. The remaining air pressure beneath the product diaphragm 61 is vented through the passage 78 to the blind opening and slot 43 leading to the generally peripheral groove 44 that is now aligned with a vertical passageway 77 leading to the chamber 66 above the diaphragm 61. A vent passage 80 communicates between the chamber 66 and the exterior of the housing 33.

When the air pressure under the product diaphragm 61 has been vented to the atmosphere, the coil spring 64 above the diaphragm 61, piston rod 62 and product valve 63, spring-biases the valve 63 to closed position and shuts off flow of the product to the bottle or container. As all the valves are now completely sealed, any product or liquid trapped in the system is retained therein due to internal pressures below atmospheric. The filling tube or stem 12 is now raised and withdrawn from the bottle or container by means of the inclination of the cam ring 17 and the associated connection to the filler head 11 for lifting the latter and the filling tube from the neck of the bottle or container.

In FIGS. 13 and 14 is disclosed the components of the air/ vacuum distributing valve .19 and therebelow the product distributing valve 81, the latter disclosed in my copending patent application Ser. No. 710,051, filed Mar. 4, 1968.

The air/vacuum distributing valve 19 includes a lower rotary valve plate 82 having plural equally spaced ports 83 each receiving a depending nipple 84 connected to a flexible hose connection 45 leading to the inlet passage 24 of an upper air sensing unit 25 of a filler head 11. The upper surface of this lower plate 82 is ground and lapped for sealing contact with an upper valve plate 86 having plural ports 87 each receiving a nipple 88 connected to a flexible inlet hose 89 from an air/vacuum source. The undersurface of this upper plate has an extended arcuate channel or groove 91 communicating with a vacuum source, and a relatively short arcuate groove 92 extending through an arc of approximately 22.5 degrees communi eating with a source of air pressure, the grooves 91 and 92 communicating with the ports 83 in the lower valve plate whereby relative rotation of the upper and lower valve plates controls the air or vacuum from the source to the filler heads 11.

The upper valve plate 86 is attached to a fixed transverse member 93 having a slot or recess 94 at each end receiving an upstanding pin 95 afiixed to and projecting upwardly from the upper valve plate for retaining the latter against rotation.

Below the rotary distributing valve 19 is the product distributing valve 81 with a housing or manifold body 96 enclosing a discharge manifold connected to a centrally disposed product inlet pipe 97 from a source of supply. In the manifold body 96 is a plate 98 mounted on the inlet pipe with a slot or recess 99 in each end receiving a drive pin 101 afiixed to an upper manifold disc 102 having an annular recess 103 in its underside receiving an annular intermediate disc 104 seating in an annular upwardly opening groove 105 on a lower valve disc 106, the upper disc 102 and the lower disc 106 being rigidly connected. The underside 107 of the lower disc 106 is recessed and provided with a flat valve seat or shut-off shoe 79 providing valve means for closing off discharge to a limited number of the ports or outlets The manifold housing 96 is connected to one end of a tie bar 111 with the other end of this bar connected to the upper end of a vertical tie rod 112 which extends at its upper end through a horizontal slide ring 113 rotatable with a bed plate 114 through suitable drive means such as a ring gear 115. Mounted on the slide ring 113 are vertical slide bars or gibs 116 each carrying a slide roller 117 and at its lower end a filler unit 10 rotatable with its bottle or container 16 to be filled carried by the bed plate 114. Thus lowering and raising of the successive filler units 10 is controlled by the slide rollers 117 each carried by its slide bar or gib 116 when engaging the inclined cam surfaces 118 and 119 on the ring cam 17 as the filler units rotate in a clockwise direction whereby the Weight of each filler unit 10 permits the latter to lower as its slide roller 117 follows the downward incline 118 of the cam surface until its filling tube enters the aligned container 16 for sensing and filling. When each container is filled, its slide roller 117 and filling tube or stem 12 are elevated by this roller riding over the upward inclination of the cam surface 119 of the ring cam 17. The height of the ring cam 17 with its inclined camming surfaces 118 and 119 is vertically adjustable by means of adjusting screws 121 to accommodate bottles or containers 16 of difierent dimensions.

Having thus disclosed my invention, I claim: 1. In a rotary filling machine for filling leakproof containers with liquid, a filler head provided with a depending filler stem having an air vent tube and a coextensive product depensing tube open at their lower ends, cam-actuated means for lowering the filler head with its depending filler stem, a sealing rubber on the filler stem adapted when lowered to engage and seal the neck of a container to be filled with the open end of the filler stem depending into the container, an air sensing unit including a reciprocable plunger and a first flexible diaphragm secured in said filler head and adjacent one end of the plunger, a reciprocable product valve carried by a second flexible diaphragm and resiliently biased to closed position, a chamber receiving said product valve and having a valve seat therefor, a source of product supply communicating with said chamber and communicating with said product dispensing tube through said valve seat, means to supply air and/or vacuum to said filler head, said reciprocable plunger being movable between a neutral position, a dispensing position and a shut-off position, said plunger being ported so that in the neutral position, a low pressure air supply communicates with said air vent tube, in the dispensing positon, a vacuum source communicates with said air vent tube and a high pressure air source communicates with said second diaphragm to open said product valve, and in the shut-off position, the second diaphragm is vented to atmosphere, passage means communicating said vent tube with said first flexible diaphragm whereby said low pressure air supply and said vacuum source can act on said first flexible diaphragm to shift said reciprocable plunger to said dispensing position and said shut-off position, and means for moving said reciprocable plunger to said neutral position.

2. In a rotary filling machine as set forth in claim 1, in which said plunger provides a ported valve for directing and controlling air flow through said air sensing unit and into and through said air vent tube into a sealed container to determine whether the container is devoid of any leak.

3. In a rotary filling machine as set forth in claim 2, wherein said passage means include a separate passage communicating between said air vent tube and one side of said first diaphragm, such that when a sealed container is leakproof, pressure is exerted through said separate passage against said diaphragm to shift said plunger from a neutral position to a product dispensing position.

4. In a rotary filling machine as set forth in claim 1, including a source of low pressure air/vacuum and a separate source of high pressure air, a first passage communicating with said ported plunger and leading to said vent tube, a second passage communicating with said plunger, and leading to the underside of said second diaphragm, and said passage means comprises a third passage communicating between said vent tube and one side of said first diaphragm, and said plunger having a first port for controlling the flow of low pressure air through said first passage, a second spaced port controlling the flow of low pressure air/vacuum through said first passage, and a third spaced port controlling the fiow of high pressure air through said second passage.

5, In a rotary filling machine as set forth in claim 4, in which said second port communicates with said first passage simultaneously with said third port communicating with said second passage, and said means for actuating said plunger comprises a rod linkage actuated by a cam to shift said plunger from a shut-off position to a neutral position with said first port communicating with said first passage, so that when a sealed container is leakproof, said low air pressure is exerted through said third passage to said first diaphragm to cause said diaphragm to shift said plunger from the neutral position to a dispensing position with said second port and said third port communicating with said first and second passages, respectively.

6. In a rotary filling machine as set forth in claim 5, in which said source of low air pressure and/ or vacuum is an air/vacuum distributing valve which supplies low pressure air when said plunger is in neutral position and privides a vacuum when said plunger is in dispensing position, said product valve being actuated by said high pressure air source when said plunger is in dispensing position, and said filler stem is cam-actuated to elevated position with said stem within the open end of said container whereby the container being filled is unsealed and opened to the atmosphere for rapid product flow.

7. In a rotary filling machine as set forth in claim 6, in which the prodcut continues to flow until the liquid level reaches and clogs the open end of the vent tube, and the vacuum in said first passage communicates through said third passage with said one side of the first diaphragm to cause said diaphragm to shift said plunger through said neutral position to the shut-off position, whereby the air pressure holding the product valve open is relieved and the resiliently-biased product valve is moved to closed position.

8. In a rotary filling machine as set forth in claim 7, in which said low pressure air initially blows out the air vent tube, an air vent passage to the atmosphere communicating with a chamber above said second diaphragm, a fourth passage extending between said plunger and said air vent passage, and fourth port partially through said plunger and extending laterally to a peripheral groove around said plunger, said groove communicating with said fourth passage when said plunger is in its shut-01f position and said fourth port communicating 5 with said second passage to relieve the air pressure heneath said second diaphragm.

9. in a rotary filling machine as set forth in claim 5, including a plunger extension on the opposite side of said first diaphragm and having an annular enlargement separating an annular groove from a reduced diameter end, and spring-biased balls urged inwardly to engage said extension to positively retain said plunger in any one of its three positions.

References Cited UNITED STATES PATENTS LAVERNE D. GEIGER, Primary Examiner E. J. EARLS, Assistant Examiner US. Cl. X.R. 

